The so-called diseases of western civilization (chronic conditions such as arthritis, asthma, osteoporosis, and atherosclerosis, other cardiovascular diseases, cancers of the breast, prostate and colon, metabolic syndrome-related conditions such as diabetes and polycystic ovary syndrome (PCOS), neurodegenerative conditions such as Parkinson's and Alzheimer's, and ophthalmic diseases such as macular degeneration) are now increasingly being viewed as secondary to chronic inflammatory conditions and adiposity. A direct link between adiposity and inflammation has recently been demonstrated. Macrophages, potent donors of pro-inflammatory signals, are nominally responsible for this link: Obesity is marked by macrophage accumulation in adipose tissue (Weisberg S P et al [2003] J. Clin Invest 112: 1796-1808) and chronic inflammation in fat plays a crucial role in the development of obesity-related insulin resistance (Xu H, et al [2003] J. Clin Invest. 112: 1821-1830). Inflammatory cytokine IL-18 is associated with PCOS, insulin resistance and adiposity (Escobar-Morreale H F, et al [2004] J. Clin Endo Metab 89: 806-811). Systemic inflammatory markers such as CRP are associated with unstable carotid plaque, specifically, the presence of macrophages in plaque, which is associated with instability can lead to the development of an ischemic event (Alvarez Garcia B et al [2003] J Vasc Surg 38: 1018-1024). There are documented cross-relationships between these risk factors. For example, there is higher than normal cardiovascular risk in patients with rheumatoid arthritis (RA) (Dessein P H et al [2003] Arthritis Res. 4: R5) and elevated C-peptide (insulin resistance) is associated with increased risk of colorectal cancer (Ma J et al [2004] J. Natl Cancer Inst 96:546-553) and breast cancer (Malin A. et al [2004] Cancer 100: 694-700).
The genesis of macrophage involvement with diseased tissues is not yet fully understood, though various theories postulating the “triggering” effect of some secondary challenge (such as viral infection) have been advanced. What is observed is vigorous crosstalk between macrophages, T-cells, and resident cell types at the sites of disease. For example, the direct relationship of macrophages to tumor progression has been documented. In many solid tumor types, the abundance of macrophages is correlated with prognosis (Lin E Y and Pollard J W [2004] Novartis Found Symp 256: 158-168). Reduced macrophage population levels are associated with prostate tumor progression (Yang G et al [2004] Cancer Res 64:2076-2082) and the “tumor-like behavior of rheumatoid synovium” has also been noted (Firestein G S [2003] Nature 423: 356-361). At sites of inflammation, macrophages elaborate cytokines such as interleukin-1-beta and interleukin-6.
A ubiquitous observation in chronic inflammatory stress is the up-regulation of heat shock proteins (HSP) at the site of inflammation, followed by macrophage infiltration, oxidative stress and the elaboration of cytokines leading to stimulation of growth of local cell types. For example, this has been observed with unilateral obstructed kidneys, where the sequence results in tubulointerstitial fibrosis and is related to increases in HSP70 in human patients (Valles, P. et al [2003] Pediatr Nephrol. 18: 527-535). HSP70 is required for the survival of cancer cells (Nylandsted J et al [2000] Ann NY Acad Sci 926: 122-125). Eradication of glioblastoma, breast and colon xenografts by HSP70 depletion has been demonstrated (Nylansted J et al [2002] Cancer Res 62:7139-7142; Rashmi R et al [2004] Carcinogenesis 25: 179-187) and blocking HSF1 by expressing a dominant-negative mutant suppresses growth of a breast cancer cell line (Wang J H et al [2002] BBRC 290: 1454-1461). It is hypothesized that stress-induced extracellular HSP72 promotes immune responses and host defense systems. In vitro, rat macrophages are stimulated by HSP72, elevating NO, TNF-alpha, IL-1-beta and IL-6 (Campisi J et al [2003] Cell Stress Chaperones 8: 272-86). Significantly higher levels of (presumably secreted) HSP70 were found in the sera of patients with acute infection compared to healthy subjects and these levels correlated with levels of IL-6, TNF-alpha, IL-10 (Njemini R et al [2003] Scand. J. Immunol 58: 664-669). HSP70 is postulated to maintain the inflammatory state in asthma by stimulating pro-inflammatory cytokine production from macrophages (Harkins M S et al [2003] Ann Allergy Asthma Immunol 91: 567-574). In esophageal carcinoma, lymph node metastasis is associated with reduction in both macrophage populations and HSP70 expression (Noguchi T. et al [2003] Oncol. 10: 1161-1164). HSPs are a possible trigger for autoimmunity (Purcell A W et al [2003] Clin Exp Immunol. 132: 193-200). There is aberrant extracellular expression of HSP70 in rheumatoid joints (Martin C A et al [2003] J. Immunol 171: 5736-5742). Even heterologous HSPs can modulate macrophage behavior: H. pylori HSP60 mediates IL-6 production by macrophages in chronically inflamed gastric tissues (Gobert A P et al [2004] J. Biol. Chem 279: 245-250).
In addition to immunological stress, a variety of environmental conditions can trigger cellular stress programs. For example, heat shock (thermal stress), anoxia, high osmotic conditions, hyperglycemia, nutritional stress, endoplasmic reticulum (ER) stress and oxidative stress each can generate cellular responses, often involving the induction of stress proteins such as HSP70.
About 40,000 women will die from metastatic breast cancer in the U.S. this year. Current interventions focus on the use of chemotherapeutic and biological agents to treat disseminated disease, but these treatments almost invariably fail in time. At earlier stages of the disease, treatment is demonstrably more successful: systemic adjuvant therapy has been studied in more than 400 randomized clinical trials, and has proven to reduce rates of recurrence and death more than 15 years after treatment (Hortobagyi G N. (1998) N Engl J Med. 339 (14): 974-984). The same studies have shown that combinations of drugs are more effective than just one drug alone for breast cancer treatment. However, such treatments significantly lower the patient's quality of life, and have limited efficacy. Moreover, they may not address slow-replicating tumor reservoirs that could serve as the source of subsequent disease recurrence and metastasis. A successful approach to the treatment of recurrent metastatic disease must address the genetic heterogeneity of the diseased cell population by simultaneously targeting multiple mechanisms of the disease such as dysregulated growth rates and enhanced survival from (a) up-regulated stress-coping and anti-apoptotic mechanisms, and (b) dispersion to sequestered and privileged sites such as spleen and bone marrow. Cellular diversification, which leads to metastasis, produces both rapid and slow growing cells. Slow-growing disseminated cancer cells may differ from normal cells in that they are located outside their ‘normal’ tissue context and may up-regulate both anti-apoptotic and stress-coping survival mechanisms. Global comparison of cancer cells to their normal counterparts reveals underlying distinctions in system logic. Cancer cells display up-regulated stress-coping and anti-apoptotic mechanisms (e.g. NF-kappa-B, Hsp-70, MDM2, survivin etc.) to successfully evade cell death (Chong Y P, et al. (2005) Growth Factors. September; 23 (3): 233-44; Rao R D, et al (2005) Neoplasia. October; 7 (10): 921-9; Nebbioso A, et al (2005) Nat Med. January; 11 (1): 77-84). Many tumor types contain high concentrations of heat-shock proteins (HSP) of the HSP27, HSP70, and HSP90 families compared with adjacent normal tissues (Ciocca at al 1993; Yano et al 1999; Cornford at al 2000; Strik et al 2000; Ricaniadis et al 2001; Ciocca and Vargas-Roig 2002). The role of HSPs in tumor development may be related to their function in the development of tolerance to stress (Li and Hahn 1981) and high levels of HSP expression seem to be a factor in tumor pathogenesis. Among other mechanisms individual HSPs can block pathways of apoptosis (Volloch and Sherman 1999). Studies show HSP70 is required for the survival of cancer cells (Nylandsted J, Brand K, Jaattela M. (2000) Ann N Y Acad Sci. 926: 122-125). Eradication of glioblastoma, breast and colon xenografts by HSP70 depletion has been demonstrated, but the same treatment had no effect on the survival or growth of fetal fibroblasts or non-tumorigenic epithelial cells of breast (Nylandsted J, et al (2002) Cancer Res. 62 (24): 7139-7142; Rashmi R, Kumar S, Karunagaran D. (2004) Carcinogenesis. 25 (2): 179-187; Barnes J A, et al. (2001) Cell Stress Chaperones. 6 (4): 316-325) and blocking HSF1 by expressing a dominant-negative mutant suppresses growth of a breast cancer cell line (Wang J H, et al. (2002) Biochem Biophys Res Commun. 290 (5): 1454-1461). Stress can also activate the nuclear factor kappa B (NF-kappa B) transcription factor family. NF-kappa-B is a central regulator of the inflammation response that regulates the expression of anti-apoptotic genes, such as cyclooxygenases (COX) and metalloproteinases (MMPs), thereby favoring tumor cell proliferation and dissemination. NF-kappa-B can be successfully inhibited by peptides interfering with its intracellular transport and/or stability (Butt A J, et al. (2005) Endocrinology. July; 146 (7): 3113-22). Human survivin, an inhibitor of apoptosis, is highly expressed in various tumors (Ambrosini G, Adida C, Altieri D C. (1997) Nat. Med. 3 (8): 917-921) aberrantly prolonging cell viability and contributing to cancer. It has been shown that ectopic expression of survivin can protect cells against apoptosis (Li F, et al. (1999) Nat. Cell Biol. 1 (8): 461-466). Tumor suppressor p53 is a transcription factor that induces growth arrest and/or apoptosis in response to cellular stress. Peptides modeled on the MDM2-binding pocket of p53 can inhibit the negative feedback of MDM2 on p53 commonly observed in cancer cells (Midgley C A, et al. (2000) Oncogene. May 4; 19 (19): 2312-23; Zhang R, et al. (2004) Anal Biochem. August 1; 331 (1): 138-46). The role of protein degradation rates and the proteasome in disease has recently come to light. Inhibitors of HSP90 (a key component of protein degradation complexes) such as bortezomib are in clinical testing and show promise as cancer therapeutics (Mitsiades C S, et al. 2006 Curr Drug Targets. 7(10):1341-1347). A C-terminal metal-binding domain (MBD) of insulin-like growth factor binding protein-3 (IGFBP-3) can rapidly (<10 min) mobilize large proteins from the extracellular milieu into the nuclei of target cells (Singh B K, et al. (2004) J Biol Chem. 279: 477-487). Here we extend these observations to show that MBD is a systemic ‘guidance system’ that attaches to the surface of red blood cells and can mediate rapid intracellular transport of its ‘payload’ into the cytoplasm and nucleus of target cells at privileged sites such as spleen and bone marrow in vivo. The amino acid sequence of these MBD peptides can be extended to include domains known to inhibit HSP, survivin, NF-kappa-B, proteasome and other intracellular mechanisms. The MBD mediates transport to privileged tissues and intracellular locations (such as the nucleus) in the target tissue. In this study we ask whether such MBD-tagged peptides might act as biological modifiers to selectively enhance the efficacy of existing treatment modalities against cancer cells. Patients presenting with metastatic disease generally face a poor prognosis. The median survival from the time of initial diagnosis of bone metastasis is 2 years with only 20% surviving 5 years (Antman et al. (1999) JAMA.; 282: 1701-1703; Lipton A. (2005) North American Pharmacotherapy: 109-112). A successful systemic treatment for recurrent metastatic disease is the primary unmet medical need in cancer.
Diabetes is a rapidly expanding epidemic in industrial societies. The disease is caused by the body's progressive inability to manage glucose metabolism appropriately. Insulin production by pancreatic islet cells is a highly regulated process that is essential for the body's management of carbohydrate metabolism. In diabetes, these cells are lost or impaired, and efforts to stimulate the body's ability to generate new islet cells have met with limited success. The INGAP peptide IGLHDPSHGTLPNGS (SEQ ID NO: 1) has been used to stimulate differentiation of islet cell precursors in cell culture and animal models (Petropavlovskaia M., et al (2006) J Endocrinol. 191(1): 65-81; Yamaoka T, Itakura M. (1999) Int J Mol Med. 3(3): 247-61; Rosenberg L. (1998) Microsc Res Tech. 43(4): 337-46), however delivery of the peptide in vivo is complicated, possibly for lack of a suitable delivery mechanism. The INGAP protein, from which the peptide sequence is derived, works primarily at an intracellular location. There is thus a need for suitable delivery technologies to deliver the INGAP peptide or protein therapeutically to the appropriate cellular locations in the body.
Familial mutations in parkin gene are associated with early-onset PD. Parkinson's disease (PD) is characterized by the selective degeneration of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc). A combination of genetic and environmental factors contributes to such a specific loss, which is characterized by the accumulation of misfolded protein within dopaminergic neurons. Among the five PD-linked genes identified so far, parkin, a 52 kD protein-ubiquitin E3 ligase, appears to be the most prevalent genetic factor in PD. Mutations in parkin cause autosomal recessive juvenile parkinsonism (AR-JP). The current therapy for Parkinson's disease is aimed to replace the lost transmitter, dopamine. But the ultimate objective in neurodegenerative therapy is the functional restoration and/or cessation of progression of neuronal loss (Jiang H, et al [2004] Hum Mol Genet. 13 (16): 1745-54; Muqit M M, et al [2004] Hum Mol Genet. 13 (1): 117-135; Goldberg M S, et al [2003]J Biol Chem. 278 (44): 43628-43635). Over-expressed parkin protein alleviates PD pathology in experimental systems. Recent molecular dissection of the genetic requirements for hypoxia, excitotoxicity and death in models of Alzheimer disease, polyglutamine-expansion disorders, Parkinson disease and more, is providing mechanistic insights into neurotoxicity and suggesting new therapeutic interventions. An emerging theme is that neuronal crises of distinct origins might converge to disrupt common cellular functions, such as protein folding and turnover (Driscoll M, and Gerstbrein B. [2003] Nat Rev Genet. 4(3): 181-194). In PC12 cells, neuronally differentiated by nerve growth factor, parkin overproduction protected against cell death mediated by ceramide Protection was abrogated by the proteasome inhibitor epoxomicin and disease-causing variants, indicating that it was mediated by the E3 ubiquitin ligase activity of parkin. (Darios F. et al [2003] Hum Mol Genet. 12 (5): 517-526). Overexpressed parkin suppresses toxicity induced by mutant (A53T) and wt alpha-synuclein in SHSY-5Y cells (Oluwatosin-Chigbu Y. et al [2003] Biochem Biophys Res Commun. 309 (3): 679-684) and also reverses synucleinopathies in invertebrates (Haywood A F and Staveley B E. [2004] BMC Neurosci. 5(1): 14) and rodents (Yamada M, Mizuno Y, Mochizuki H. (2005) Parkin gene therapy for alpha-synucleinopathy: a rat model of Parkinson's disease. Hum Gene Ther. 16(2): 262-270; Lo Bianco C. et al [2004] Proc Natl Acad Sci USA. 101(50): 17510-17515). On the other hand, a recent report claims that parkin-deficient mice are not themselves a robust model for the disease (Perez F A and Palmiter R D [2005] Proc Natl Acad Sci USA. 102 (6): 2174-2179). Nevertheless, parkin therapy has been suggested for PD (Butcher J. [2005] Lancet Neurol. 4(2): 82).
Variability within patient populations creates numerous problems for medical treatment. Without reliable means for determining which individuals will respond to a given treatment, physicians are forced to resort to trial and error. Because not all patients will respond to a given therapy, the trial and error approach means that some portion of the patients must suffer the side effects (as well as the economic costs) of a treatment that is not effective in that patient.
For some therapeutics targeted to specific molecules within the body, screening to determine eligibility for the treatment is routinely performed. For example, the estrogen antagonist tamoxifen targets the estrogen receptor, so it is normal practice to only administer tamoxifen to those patients whose tumors express the estrogen receptor. Likewise, the anti-tumor agent trastuzumab (HERCEPTIN®) acts by binding to a cell surface molecule known as HER2/neu; patients with HER2/neu negative tumors are not normally eligible for treatment with trastuzumab. Methods for predicting whether a patient will respond to treatment with IGF-I/IGFBP-3 complex have also been disclosed (U.S. Pat. No. 5,824,467), as well as methods for creating predictive models of responsiveness to a particular treatment (U.S. Pat. No. 6,087,090).
IGFBP-3 is a master regulator of cellular function and viability. As the primary carrier of IGFs in the circulation, it plays a central role in sequestering, delivering and releasing IGFs to target tissues in response to physiological parameters such as nutrition, trauma, and pregnancy. IGFs, in turn, modulate cell growth, survival and differentiation, Additionally, IGFBP-3 can sensitize selected target cells to apoptosis in an IGF-independent manner. The mechanisms by which it accomplishes the latter class of effects is not well understood but appears to involve selective cell internalization mechanisms and vesicular transport to specific cellular compartments (such as the nucleus, where it may interact with transcriptional elements) that is at least partially dependent on transferrin receptor, integrins and caveolin.
The inventor has previously disclosed certain IGFBP-derived peptides known as “MBD” peptides (U.S. patent application publication nos. 2003/0059430, 2003/0161829, and 2003/0224990). These peptides have a number of properties, which are distinct from the IGF-binding properties of IGFBPs, that make them useful as therapeutic agents. MBD peptides are internalized some cells, and the peptides can be used as cell internalization signals to direct the uptake of molecules joined to the MBD peptides (such as proteins fused to the MBD peptide).
All references cited herein, including patent applications and publications, are incorporated by reference in their entirety.